As set forth in the above referenced patents, the air cushion type undercarriage concept for airplanes provides many advantages over prior type skid, pontoon, and/or wheel type systems; in that basically the air cushion undercarriage system when properly applied enables an airplane to land/rest/take-off from a large variety of surfaces as aforesaid. However, previously proposed air cushion type undercarriage systems have inherently encountered either performance or structural complication problems which have handicapped advancement and pragmatic acceptance of the basic advantages of the airplane air cushion undercarriage concept. Prior designs employed structurally obvious engineeringly advantageous designs based on air cushion supply boundary trunk support means as typically provided under the main aircraft structural frame/fuselage/hull of the airplane, and/or extensible outriggers therefrom. In consequence the lateral (anti-roll) support "track width" thereof (which controls stability in roll characteristics of the airplane during landing/take-off/flotation operations) has been heretofore undesirably limited by necessary trade-off design considerations. These include; what are the available sheet materials of desired elasticity capabilities for use in fabricating the trunk system, and/or should there be employed a mechanically complicated trackwise extension equipment such as suggested for example in U.S. Pat. No. 4,004,761?
The present invention provides a basic solution to the aforesaid problems in that it contemplates a novel frontal and planform profile airplane wing design, in combination with an improved "track width" configured air cushion supply elastic trunk arrangement. The term "maximum track width" as will be used hereinafter refers to the maximum outside width dimension of the inter-surface reaction effect of the trunk (when inflated) with a runway/water surface or the like as explained hereinabove. This may also be referred to as the "outside footprint width" dimension of the undercarriage; which determines the stability in roll (or "roll stability") characteristics of the craft when in air cushion and/or ground/water support regime. By virtue of this invention, an increased "track area" is obtained without excess demands upon current technology in the elastic and air-impervious sheet fabric manufacturing process; and also without requiring employment of mechanically complicated /expensive and aerodynamically handicapping extensible-retractable outrigger arrangements such as have been suggested by the prior art, with a view to improving the anti-roll stability characteristics of an airplane with operating in the air cushion undercarriage supported mode.